1. Field of the Invention
The present invention relates to data acquisition and logging systems for subsurface resource drilling, and more particularly relates to generating data for logging.
2. Related Art
The exploration for subsurface resources such as hydrocarbons including oil and gas, minerals and water, typically requires various techniques for determining the characteristics of geological formations. Many characteristics, such as the hydrocarbon volume, resistivity, porosity, lithology, and permeability of a formation, may be deduced from certain measurable quantities associated with the geological formations. It is a well-known technique to measure these characteristics, i.e., measured variables, by drilling a well in conjunction with a data acquisition and logging system.
Much of the information acquired by such a system is acquired by a sensor-equipped drilling tool and is categorized as either xe2x80x9creal-time or recordedxe2x80x9d xe2x80x9cmode data.xe2x80x9d The term xe2x80x9creal-timexe2x80x9d data, as used herein, includes data acquired while the logging tool is in the well and transmitted to the surface and recorded shortly after being acquired. That is, transmitting and recording is typically substantially completed while the logging tool is in the well, which requires transmitting by a method with limited bandwidth, such as mud-pulse telemetry. The limited data transfer rates of down-hole telemetry systems reduces the number of transmission and recording channels, the sample interval, or both. Consequently only a subset of the recorded data can typically be transmitted as real-time data.
In the xe2x80x9crecorded mode,xe2x80x9d data is acquired and stored in a memory device of the logging tool. The recorded data may be subsequently retrieved from the memory when the logging tool is brought to the surface. The term xe2x80x9crecorded data,xe2x80x9d as used herein, includes data stored in the memory of the logging tool while the logging tool is in the well. Thus, recorded data are distinct from real-time data.
Another category of information acquired by a data acquisition and logging system is data acquired by surface measurement devices, which are typically located above ground. Surface measurements generally include depth and other measurements, such as hookload and surface torque. Depth measurement is computed by measuring the length of a drill string.
Aside from the above, information acquired by a data acquisition and logging system may also be categorized according to states, i.e., xe2x80x9cmodes,xe2x80x9d of the drilling rig while the data is acquired. It is well known that the drilling rig can be operated in several modes such as drilling, reaming, and tripping to penetrate the geological formations. For example, during the drilling operation the drilling bit is described as being xe2x80x9con-bottomxe2x80x9d. (It should be understood that the term xe2x80x9cdrillingxe2x80x9d has a rather specific meaning when used in the context of operating in a xe2x80x9cdrilling mode,xe2x80x9d as just described. The term xe2x80x9cdrillingxe2x80x9d may also be used in a more general sense, such as in the context of xe2x80x9cdrilling the wellxe2x80x9d or xe2x80x9cmeasurement while drillingxe2x80x9d (xe2x80x9cMWDxe2x80x9d), which are mentioned herein below.) In the reaming operation, the logging tool is rotating or not rotating and the bit is xe2x80x9coff-bottomxe2x80x9d (i.e. not drilling), regardless of whether the drilling tool is moving up or down. In the tripping mode the drilling tool is being lowered into or pulled out of the oil well, but generally is not rotating. For the purposes of this invention, xe2x80x9creamingxe2x80x9d covers both tripping and reaming.
A drilling rig is typically capable of operating only in one mode at a given instant. For example, the rig cannot be reaming and drilling at the same time. Consequently, when the rig is reaming toward bottom, the rig mode automatically changes to the drilling mode as soon as the bit touches the bottom of the hole. Therefore, in data acquisition terms, data acquired in a reaming operation is not xe2x80x9con-bottomxe2x80x9d.
In addition to acquiring measured variables in numerous categories, the above described measurements are, of course, made at a multitude of successive depths. Moreover, numerous instances of the respective measurements are often made at a single depth. For example, a first instance of each measurement is made while a drill bit, drilling the well, is on-bottom and additional instances of the measurement are made as the drill bit is raised up (xe2x80x9creaming upxe2x80x9d) or lowered back down (xe2x80x9creaming downxe2x80x9d). That is, depth intervals are re-traversed selectively while measuring continues. Once the drill bit gets back to the bottom of the well, i.e., back xe2x80x9con-bottom,xe2x80x9d new instances of the measurements are made at successive new depths.
From the above it should be appreciated that information acquired by a data acquisition and logging system is typically voluminous. In addition, the data acquired in well logging may be acquired over a period of days, weeks or even months. Consequently, the system automatically processes data as it is acquired to make the data more manageable and accessible. For example, a set of data of particular interest is typically identified by the well logging system by automatically generating a data file for it. One such automatically generated file is a depth-versus-time data file, which has records for data that is acquired on-bottom.
It is often necessary to manually edit these well logging data files, particularly those that are generated automatically. For example, on-bottom data collected by a failed sensor may require a substitution for the xe2x80x98badxe2x80x99 on-bottom data of off-bottom data that has been collected by an alternate sensor. This manual editing is, of course, made more complex by the volume and variety of data, as described above.
As another example, length of a drill string is typically used to measure depth of the well. The length of the drill string may vary depending on various factors such as tension and temperature. Thus, raw depth measurement data for depth measurement is calibrated manually at a predefined periodic depth interval. The raw depth measurement data is combined with the manually entered depth measurement data to generate corrected depth measurement data.
Despite the complexity of the editing process for well logging data, conventional systems generally have only limited tools for manipulating data records. Therefore a need exists for improvements in such tools.
The foregoing need is addressed by the present invention, according to which a graphical user interface (xe2x80x9cGUIxe2x80x9d) of a well logging display program includes multiple windows and controls for user interaction and editing of data records included in well logging data. The well logging data includes records of logging variables measured at successive depths. The windows include a first window for displaying depth versus time measurements, a second window for selecting one of the logging variables, a third window for selecting and displaying a first set of instances of the logging variable, and a fourth window for selecting and displaying a second set of instances of the logging variable. The controls include a bar line for selecting a splice point, and an interface button for instructing the program to edit the data records. The data records resulting from the editing include measurements corresponding to the first and second set of instances spliced in accordance with a predefined function.